The oil refinery at Grangemouth, Scotland, UK.
Photograph: Murdo Macleod for the Guardian

What does it mean for a nation to be a “climate leader” in 2018?

At the very least, it must mean having a firm plan in place to deliver your nation’s fair share of the Paris agreement. During that stunning fortnight in December 2015, 195 governments freely and willingly committed not only to keep global warming well below 2C, but to aim for the safer level of 1.5C. And they committed to bring net greenhouse gas emissions down to zero.

I cannot help but feel huge pride that my government was the first in the western world to step up and deliver on the Paris agreement. In June last year, we adopted a target of cutting Sweden’s net greenhouse gas emissions to zero by 2045, and we set it in law. Within a generation, Sweden will not be contributing to the problem of climate change. Science tells us that if all nations adopt this target, there is a good chance that we will live up to the commitments that we made at the Paris summit, and keep climate change within safe boundaries.

Our law does not only set an emissions target and a date. Every year the government must present a progress report to parliament, and every four years it must make a new set of policies that deliver ever-greater emission cuts. This way we will ensure that we will make steady progress towards our net-zero target.

For these ingredients of our law, we owe the UK a debt of gratitude. Ten years ago, the UK brought in the first law in the world that set a legally binding target for reducing greenhouse gas emissions. Sweden borrowed heavily from the UK Climate Change Act in drawing up our own, as have other countries such as Denmark and Finland.

Climate laws deliver something that in a healthy democracy is invaluable for businesses and citizens: certainty. Our companies know that fossil fuels will be virtually eliminated over the next 25 years; coal has already gone, and oil and gas will follow. Certainty helps citizens, companies, investors and the government itself to make better decisions. For example, it is clearly good sense that all new houses are built so as to waste very little energy, so eliminating the need for more expensive retro-fitting in a decade’s time.

A number of other countries have stepped up since the Paris summit by committing to net zero emissions targets by 2040 or 2050. They include France, Iceland and New Zealand – but also some developing nations such as Costa Rica and Bhutan. Driven by a progressive alliance including Sweden and the UK, the European Union is heading in the same direction. The EU parliament has already voted for a net zero target, and the commission is updating its energy and climate roadmap in line with the Paris agreement – a process which will inevitably recommend a net zero target for the EU with a target date no later than 2050.

More nations will inevitably follow later this year. In October the UN’s Intergovernmental Panel on Climate Change (IPCC) will publish a landmark report which is expected to confirm that the world will need to be at net zero emissions by mid-century in order to deliver on the Paris agreement. Those countries where finance and modern technology are more available will naturally be expected to take the lead in getting there. The IPCC is an intergovernmental body – so at that point, it will clearly be untenable for any western government that does not have a net zero target with an appropriate date and a means of delivering it to claim to be a “climate leader”.

Meeting a net zero target will not be easy for all sectors of the economy. We know how to do it for electricity, heating and road transport; for others such as agriculture and aviation it will be more challenging. Here, we must trust to innovation, the speed of which continues to amaze. And we can accelerate changes in these sectors with specific financial instruments such as the aviation tax that Sweden introduced this month.

Certainly it is not acceptable for any government or statutory adviser to say that net zero cannot be done. It has to be done – because as long as we continue emitting carbon dioxide, temperatures will continue to rise. Claiming that net zero is impossible would mean giving up on the imperative of halting climate change; accepting that we will never hold back the tide of rising sea levels, failing food supplies, species extinctions and an acidifying ocean. That is not a world that I can bequeath to my children and grandchildren; nor, I believe, can any responsible leader.

Ten years ago, the UK won the gratitude of many other nations, including my own, by adopting the Climate Change Act. But science and diplomacy move on; and when the IPCC and the Paris agreement are telling us that greenhouse gas emissions need to reach net zero by mid-century, it is incumbent on us all to reflect that in our national programmes. That, at the very least, is what it means in 2018 to be a “climate leader”.

• Isabella Lövin is deputy prime minister of Sweden, and minister for international development, cooperation and climate